The high technologies employed nowadays in numerous optical and mechanical systems, often require surfaces produced with submicronic precision. In addition to mastering the machining processes, there is the problem of quality control of the obtained components.
U.S. Pat. No. 5,066,119 describes an optical device, adapted for the control, by phase detection, of any surface of an optical system, comprising essentially, along an optical path: emission means adapted to constitute a light source, a reflecting surface to be tested, a separator cube disposed between the light source and the surface to be tested and provided with a semi-reflecting surface to divert the light beam reflected by the surface to be tested, a grating such as a Ronchi grating, disposed adjacent the point of convergence of said reflected light beam, an objective to give the image observable in the analysis plane of a camera with a charge coupled device (CCD), which is to say in the plane of the CCD detector, and a camera coupled to data processing means for use of the image by phase detection.
This optical device, of the deflectometer type, with phase detection, permits precise and rapid measurement, for any surface, and without contact, of a large variety of optical and aspherical surfaces, without specific tools. It has however, by virtue of its principle, limits in terms of the diameter of the measurable range, particularly because of the entrance pupil of its acquisition system.